Senior Software Developer - LLM Tooling & Code Modernization

Bentley Systems; Dublin; Hybrid; EUR 120,000 - 160,000; Full time

Job summary

Bentley Systems in Dublin, Ireland, seeks a Senior Software Developer to architect and deliver LLM-powered tooling for code modernization. You will lead multi-agent workflows across large-scale engineering software projects, turning ambiguous problems into executable plans while maintaining code integrity.

You will own end-to-end delivery, build automated pipelines, and collaborate with partner teams to deploy reliable modernization tooling at scale.

Qualifications

• Strong software development experience with ownership of production systems and complex existing codebases.
• Demonstrated self-directed delivery: defined and solved underspecified problems without step-by-step supervision.
• Hands-on LLM or coding-agent experience beyond code completion with concrete automation examples.
• Experience building developer tools, pipelines, or integrations that multiply engineering output.
• Ability to decompose large problems, delegate parallel tasks, and integrate results against measurable acceptance criteria.
• Strong testing, debugging, architecture, performance, and failure-analysis fundamentals; judgment about when human intervention is necessary.
• Entrepreneurial ownership: prioritize valuable work, make pragmatic tradeoffs, remove obstacles, and follow through to adoption.
• Ability to learn unfamiliar tools quickly, adapt workflows as capabilities evolve, and communicate clearly across teams.

Responsibilities

• Identify modernization opportunities and drive them from discovery to delivery, aligning priorities with partner teams.
• Build LLM-powered pipelines for code understanding, migration planning, large-scale refactoring, and validation.
• Run multiple agent-driven workstreams across projects concurrently, managing context, dependencies, failures, and integration.
• Connect agents to source code, compilers, build systems, tests, and diagnostics.
• Automate change/test/diagnose/correct loops, with clear stopping conditions and targeted human review.
• Divide migrations into independently verifiable units, preserving behavior and numerical equivalence where required.
• Replace recurring manual work with reusable tools, including automation that reduces your own supervision burden.
• Evaluate and adopt emerging tools quickly when they improve quality, throughput, reliability, or cost.
• Deliver integrated code, documented workflows, and a practical handover to product teams.

Skills

Software development

Self-directed delivery

LLM tooling

Developer tooling

Problem decomposition

Testing & debugging

Entrepreneurial ownership

Cross-team communication

Tools

Rust

C++

Fortran

LLM APIs

Job description

Bentley Systems

Senior Software Developer - LLM Tooling & Code Modernization

Location:

Hybrid - Dublin, Ireland

Position Summary

Bentley is building a specialized team to transform large, complex engineering software systems using LLM-powered tools and automation. We are looking for a highly autonomous software developer with an entrepreneurial mindset and a record of delivering results. You identify high-value opportunities, turn ambiguous problems into executable plans, and own delivery without waiting for a detailed task list. This is a software engineering and developer tooling role - not model development or ML research. Training neural networks or developing your own models is not required. You will turn existing LLMs into reliable systems for large-scale code transformation. Your impact must extend beyond the code you personally write. You will orchestrate multiple coding agents across projects, automate routine execution and verification, and resolve exceptions without becoming every workstream's bottleneck. Success means delivering more correct, integrated modernization work in less time - not simply running more agents or generating more code.

What You'll Do

• Identify modernization opportunities and drive them from discovery to delivery, aligning priorities with partner teams.
• Build LLM-powered pipelines for code understanding, migration planning, large-scale refactoring, and validation.
• Run multiple agent-driven workstreams across projects concurrently, managing context, dependencies, failures, and integration.
• Connect agents to source code, compilers, build systems, tests, and diagnostics.
• Automate change/test/diagnose/correct loops, with clear stopping conditions and targeted human review.
• Divide migrations into independently verifiable units, preserving behavior and numerical equivalence where required.
• Replace recurring manual work with reusable tools, including automation that reduces your own supervision burden.
• Evaluate and adopt emerging tools quickly when they improve quality, throughput, reliability, or cost.
• Deliver integrated code, documented workflows, and a practical handover to product teams.

Required Qualifications

• Strong software development experience with ownership of production systems and complex existing codebases.
• Demonstrated self-directed delivery: you have defined and solved underspecified problems without step-by-step supervision.
• Hands-on LLM or coding-agent experience beyond code completion, with concrete examples of useful automation.
• Experience building developer tools, pipelines, or integrations that multiply engineering output.
• Ability to decompose large problems, delegate parallel tasks, and integrate results against measurable acceptance criteria.
• Strong testing, debugging, architecture, performance, and failure-analysis fundamentals; judgment about when human intervention is necessary.
• Entrepreneurial ownership: prioritize valuable work, make pragmatic tradeoffs, remove obstacles, and follow through to adoption.
• Ability to learn unfamiliar tools quickly, adapt workflows as capabilities evolve, and communicate clearly across teams. Production work, internal tools, open-source contributions, and substantial personal projects all count. Show what you built, what it automated, and how you established that it worked - not just which AI tools you used.

Preferred Qualifications

• Experience with large-scale refactoring, legacy modernization, or cross-language migration.
• Experience with Rust, C++, C, or Fortran.
• Experience building multi-agent workflows or integrating LLM APIs with development tools.
• Background in CI/CD, automated testing, benchmarking, observability, or validation tooling.
• Experience with scientific, mathematical, engineering, or simulation software where correctness is critical.
• Familiarity with cloud platforms and distributed systems where relevant to modernization.

What Success Looks Like

• High-value initiatives move from ambiguity to usable results with minimal supervision.
• Multiple projects advance concurrently without your attention becoming the bottleneck.
• Delivery accelerates without compromising behavioral correctness or maintainability.
• Automation reduces total effort, including review, correction, and integration.
• Other developers can operate and extend your documented workflows.
• New capabilities produce measurable improvements, not just more activity.

Who Thrives in This Role

• You combine initiative, urgency, and engineering rigor. You spot opportunities, prototype quickly, and stay accountable until the result is reliable and adopted. When your attention becomes the bottleneck, you improve the system: better delegation, clearer agent responsibilities, automated verification, and exception handling - not simply longer hours. You enjoy unfamiliar codebases and rapidly evolving tools. You use LLMs to multiply your impact, never to outsource your judgment or accountability.

About Bentley Systems

Around the world, infrastructure professionals rely on software from Bentley Systems to help them design, build, and operate better and more resilient infrastructure for transportation, water, energy, cities, and more. Founded in 1984 by engineers for engineers, Bentley is the partner of choice for engineering firms and owner-operators worldwide, with software that spans engineering disciplines, industry sectors, and all phases of the infrastructure lifecycle. Through our digital twin solutions, we help infrastructure professionals unlock the value of their data to transform project delivery and asset performance. www.bentley.com

Equal Opportunity Employer

Bentley is proud to be an equal opportunity employer and considers for employment all qualified applicants without regard to race, color, gender/gender identity, sexual orientation, disability, marital status, religion/belief, national origin, caste, age, or any other characteristic protected by local law or unrelated to job qualifications.